Browsers:
- All IPv6 addresses entered into the address bar need to be enclose in brackets(RFC 2732). Example: [fe80::203:f4ff:fe08:2f9c]
- OS X cannot connect to the link local address of a webserver through a browser. I have no idea if this is a limitation of all the browser or the OS itself.
- MLD snooping is broken. While we are compatible and properly register our core addresses, most other systems do not and/or switches do not handle registrations properly. Do not use MLD snooping on an IPv6 network.